1. Field of the Invention
This invention relates to apparatus for cooling hot rubber and plastic extrudates using a gas-cooled fluidized bed to cool and to support the extrudate.
2. History of the Art
Extruded products are conventionally cooled by extruding them into a water bath or by forced air currents. Such cooling, however, is typically slow compared to the potential rate of extrusion with the result that the rate of cooling is a major limiting factor in the manufacture of extruded products.
Slow cooling not only limits the rate of manufacture it also permits physical and chemical deterioration of the extruded product and aggravates contamination of the work area. The longer the extrudate maintains an elevated temperature, the greater the thermal degradation of its color, electrical resistivity, and other physical properties, and the greater the effects of oxidative attack. Moreover, hot extrudates often exude hazardous decomposition products such as, for example, vinyl chloride monomer.
In addition, in the conventional cooling of extruded products, the extrudate is typically supported in the cooling station by one or more of a variety of mechanisms, such as plates, belts, jigs or rollers, which often distort or mar substantial portions of the soft extruded product.